Maintaining the integrity of the information contained in a computer system is of great importance to computer operators. Traditional means of limiting system access to authorized users include requiring those desiring admittance to provide identifying information including a password. This information typically is entered into the data stream between the terminal in use and the host computer and has proven to be extremely useful in distinguishing authorized from unauthorized users. In some cases, additional layers of passwords or challenges have been added. Many systems, however, require even greater security than the conventional methods provide. For these systems information obtained from sources other than the data stream, such as voice intelligence, furnishes an additional measure of protection not present in the traditional approach to computer security.